A technique that employs a metal foil strain gauge which utilizes changes in a resistance value of a metal foil as caused by strain is known as a method for measuring deformations such as strain on a measurement object. This is a technique that enables measurement of strain on the measurement object by adhesively attaching the strain gauge to the measurement object, causing the metal foil to change its length in accordance with the strain on the measurement object, and detecting changes in the resistance value of the metal foil as a result of changing its length.
A semiconductor strain sensor in which a semiconductor piezoelectric element is formed by doping a surface of a semiconductor substrate with impurities is being examined as a mechanical quantity measuring device for measuring the deformations such as the strain on the measurement object with high accuracy.
One example of such semiconductor strain sensor is known which has a structure in which a sensor chip equipped with a semiconductor strain unit is soldered onto a metallic stem and the metallic stem is adhesively attached to the measurement object by using an adhesive agent made of resin.
It is described that the metallic stem interposed between the measured object and the sensor chip reduces the strain caused on the sensor chip due to the deformations of the measurement object and prevents or inhibits breakage of the sensor chip (see PTL 1).